Analysis of the correlation between the biomarkers and subtype phenotypes of patients with SMA Type 1 indicated that the distribution of SMN2 and NAIP copies was negatively correlated with disease severity (Kendall’s tau-c = −0.907, p < 0.001; Kendall’s tau-c = −0.383, p = 0.007, respectively). Here, NAIP is linked to spinal muscular atrophy, type 1.